Providing some relief, market heavyweight Samsung Electronics Co Ltd, sold heavily in the past three days amid a phone recall crisis, recovered somewhat by 2 per cent.

Web portal Naver Corp lost more than 2 per cent.

Decliners far outnumbered advancers 607 to 184.

"BOK's decision was fully priced in, and therefore had limited impact on the market. The local currency is responding more to the dollar's movement," said Ha Keon-hyeong, an economist at Shinhan Investment Corp.

He said the US dollar could extend gains depending on US economic data in the near term.

The US dollar was boosted on Wednesday by the minutes of the Fed's September policy meeting showing several voting members of the policy committee judged a rate hike would be warranted "relatively soon" if the US economy continued to strengthen.

December futures on three-year treasury bonds gained 0.08 point to 110.70.